Milking apparatus of the automatic type is well known, and such apparatus is shown, for example, in U.S. Pat. Nos. 514,551; 2,608,951; 3,033,161; 3,079,891; 3,388,689; and 3,605,695. In addition, milker retraction apparatus for a milker has also been heretofore suggested and/or utilized, as shown, for example, by U.S. Pat. Nos. 2,641,223 and 3,738,321.
As is common with automatic milking devices, when the end of milking is determined, the apparatus must be removed from the animal and the apparatus then prepared for later milking use, with one such apparatus commonly being utilized to milk several different animals in a given time period.
Several devices have been developed for sensing the end of milking and one such device, as shown in U.S. Pat. No. 3,874,337, senses the temperature of the milk withdrawn from an animal being milked and, responsive thereto, controls withdrawal of the milking apparatus and/or indicates the presence of an abnormality, such as sensed fever.
The use of stimulation to induce milk let down in an animal to be milked has also heretofore been broadly suggested including the use of warm water, electric shock, and/or various gripping devices. For example, see U.S. Pat. Nos. 507,069; 948,440; 3,301,215; 3,366,111; and 3,406,663.
Valves have also heretofore been utilized in conjunction with cleaning of milking apparatus, and examples of such valves are shown in U.S. Pat. Nos. 1,579,796; 1,803,319; 1,837,484; 2,624,355; 2,714,893; 2,717,576; and 3,726,253. In addition, valves have heretofore been utilized having a plurality of ports (see, for example, U.S. Pat. No. 1,854,307) and sliding valves have also been utilized (see, for example, U.S. Pat. No. 2,253,341).
Stimulators and valves heretofore suggested and/or utilized have not, however, proved to be completely successful in accomplishing the desired ends, at least in some instances, and improvements therein for milking apparatus, was therefore desirable.